|LADSPA (Linux Audio Developers Simple Plugin API) is an audio plugin standard originally developed on Linux, but which can be ported to Windows and Mac too. Audacity has built-in support for LADSPA plugins.
Writing LADPSA plugins
Audacity behaves as an excellent LADSPA host. Just read up about LADSPA, and make your plugins correctly. As a starting point, look at the LADSPA developers' documentation and the LADSPA site's example plugins. Keep in mind that Audacity "runs" the plugin multiple times with some specific number of samples. So, don't assume that your plugin will get the entire selection the first time. Here is an example LADSPA plugin made by a user for plotting frequency variation.
Using LADSPA plugins
It's usually most convenient to place your LADSPA plugins in one of the following:
- any colon-delimited path specified by the LADSPA_PATH environment variable.
In addition, LADSPA plugins installed using the package manager will frequently be installed in:
Note that if building Audacity from the source code, these paths will not be seen by Audacity unless there is some other mechanism to direct Audacity to look there, for example:
- Audacity is configured to install in /usr/
- /usr/lib/ladspa or /usr/lib64/ladspa are added to the LADSPA_PATH environment variable. (See this Frequently Asked Question for information regarding the LADSPA_PATH environment variable).
Restart Audacity and the plugins should be in themenu, underneath the divider.
If you have the ladspa-sdk installed, you can run listplugins from a terminal to list all plugins in your LADSPA_PATH.
Windows and Mac OS
Audacity also supports LADSPA plugins on Windows and Mac OS. Any LADSPA plugin compiled as a Windows .dll or Mac .dylib shared library will work on these platforms. An extensive set of LADSPA plugins is available for Windows and Mac OS X.
To add LADSPA plugins to Audacity, place them in the "Plug-Ins" folder inside the Audacity installation folder. Restart Audacity and the plugins should be in the C:\Program Files on Windows, or under Mac Hard Disk > Applications on OS X.menu, underneath the divider. The Audacity installation folder is usually under
As on Linux, Audacity will also detect LADSPA plugins if you put them in a folder specified in the LADSPA_PATH environment variable.